The announcement that the United States is to deploy 24 Apache helicopters to Albania along with 2,000 supporting troops represents a significant boost to Nato airpower in the region.

The twin-engined apache is the US army's principle attack helicopter. It carries shell fire, laser-guided missiles and its role is to destroy tanks and other armoured vehicles far ahead of its own front line.

It has a crew of two, it can operate in all kinds of weather both by day and night, and it is well tried in combat. Its deployment would give Nato commanders an additional means of striking at Yugoslav forces on the ground in Kosovo.

The 24 Apaches would probably come from Germany and would be ready to operate in a matter of days if Nato gives the go ahead.

The Pentagon is presenting their deployment as a reinforcement of the Nato air campaign, not as a prelude to the opening of a ground war.

Bad weather

Ever since it began air operations over Yugoslavia, the alliance has been struggling to bring its full force to bear.

The poor weather combined with the demand to do whatever is possible to avoid civilian casualties has significantly hampered Nato's effectiveness.

While it has successfully attacked a wide range of strategic targets from petrol depots to bridges and headquarters buildings, Nato commanders now want to focus on Yugoslav police and army units in Kosovo itself.

Nato's strategy is effectively to force these units to withdraw or to destroy them if they remain.

Apache helicopters could play a key role but Yugoslav forces are dispersed widely and still have a variety of anti-aircraft weapons.

The Apache crews would be operating in a very dangerous environment and so far Nato has preferred to reduce the risks to its pilots as far as possible.